Intramusular because insulin takes too long

I would like to start a discussion with anyone who has had similar experiences. I was diagnosed at only 3 years old, I have had type 1 now for 43 years. I don’t use a pump anymore as I recently put myself back onto injections. There was a thread on here, quite recently, about fast acting insulin not working on people for two or more hours, many who have had type one for several decades.This is an interesting subject, all on it’s own, my endocrinologist said she didn’t believe me. ( her exact words were ‘that’s impossible’) when I told her how long quick acting insulin takes to work on me. If I inject humalog, apidra or novorapid subcutaneously (SC) it takes 2 hours to begin lowering my BG. To make a long story shorter, I now do IM shots in both deltoid muscles on each arm. I use 12mm 29G needles, so as IM shots go they are very small. I began doing it occasionally at first but I do this now for every bolus and correction. My CGM shows insulin working wirhin 10 to 15 mins, and pretty mich finished within an hour. I was stressed out for quite awhile both with pumping then just injecting as it makes managing BG close to impossible ( two hours is a very long time for it to start. The half life is also much shorter, this is a wonderful added bonis. So are there any comments, on your own experience with insulin taking hours to work and or experience with M shots, I am very keen to hear what others who have had diabetes for a long time who also have insulin not working as quick as it used to?

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You will get a lot of replies. My first question would be do you bolus at start of meal, end of meal or pre-bolus. Pre-bolus can have a huge impact as it is a lot easier keeping BG from raising rather than letting it climb and then bring it back down. That makes a huge timing difference.

You will probably also hear that time to take effect will greatly depend on the total number of carbs you eat per meal and your ratio of Carb/Protein/fat. We are all different and the easiest way to narrow it down is to work on 1 variable at a time and then look at CGM patterns and fix one at a time until you get where you want to be.

If you look at various Humalog data and test results done by Lilly and/or other entities, you will see a very wide range of when insulin peaks, like anywhere between 30 minutes and 3 hours.

That’s why people are loving Afrezza, much faster acting and it also has the benefit of leaving the system faster. I believe probably also a lot more predictable than muscle shots.



I have been a T1D for over 50 years. I finally have found the right way to manage my diabetes. Lots of issues to deal with. Like you, sometime it takes my pumped humulog 2 hours to start working. But other times as quickly as 30 minutes, never faster. For sure I pre-bolus before every meal and have cut back on carbs too. I think for those of us who have to worry about how fast insulin will begin to work, pre-bolus is key. And I compliment that with only eating a minimum amount of carbs at meal time and then eating snacks or dessert later when BG goes down from the bolus insulin. Works for me.

I was the one who recently started the thread on how long it takes Humalog or Fiasp to start to take effect (I have had Type I for 40 years and started on Humulin R and Humulin NPH 40 years ago). What’s funny is that Humulin R takes effect in my body just as Fiasp and Humalog (2 to 2.5 hours)! I found that Afrezza (I’ve only been taking it for 4 days) has effect within 15 to 25 minutes but is very short acting… Maybe lasts an hour… Thus, I’ve found that if I take Afrezza (12 unit) before eating and 8 units of Humulin R, I get a nice slow curve of blood sugar lowering from 180 or so to 90 due to the Afrezza and remaining in the 100-150 range due to the Humulin R…

BTW: I had the same arrogant SOB type “diabetic endocrinologist” that insisted that fast-acting insulins could NOT take 2.5 hours to work! Since I’ve been a Type I diabetic for almost 40 years, I certainly know better than some arrogant doctor how my diabetes works. I’m a farm animal veterinarian and I marvel at the fact that the farmers who are my clients know infinitely more about their herds etc than I do. I now go to a fine GP who is willing to prescribe any new type of insulin/CGM technology that I want after he researches it. That’s how I got Afrezza.

I appreciate the comment above that it’s best to take your insulin (whether inhaled or injected) BEFORE your blood sugar is too high (ie: before eating any carbs) because the insulin works much faster and better while your blood sugar is still low.

Now… totally off topic:
I still thank God every day for the Dexcom G6/XDrip+ Android that I got several months ago. It has saved me from NUMEROUS cases of insulin shock (I writhe out of bed and end up paralyzed on the floor struggling to take glucose tablets – but no insulin shock since I got my Dexcom!!!). BTW: My last sensor lasted 18 days when it was stuck down with Skin-Tac


Type 1 for 60 yrs. I notice no difference in the length of time my insulin takes to work, but I eat a diet that doesn’t change much at all. I eat at least 275 carbs a day and take 22 units of total insulin when not exercising. My diet is very low fat and plant based. Rarely is my glucose level high enough for it to take insulin long to work. I usually give my Novolog injection about 10 minutes before I eat. I am assuming that the higher the glucose level the more time it takes insulin to work properly. I may be wrong about this assumption. Once in awhile my glucose level rises and I notice that then it takes longer to get back in the 80 range.


My insulin also works super slowly. I try to use a combination of pre-bolusing and eating very slowly. I have always eaten slowly anyway, but now it is excruciatingly slow. My husband finishes dinner in 10 minutes and I take 45. I would be scared to inject in muscle because of the lack of predictability plus it’s just not something I’m used to plus I have enough trouble with scarring.

I also find it very disappointing that we were all told that we were making things up by our doctors. Not surprising, but disappointing. They want things to be so much simpler than they are, and blame us when experience doesn’t match up with what they think is “logical”. Isn’t it logical to assume bodies are different and behave differently?

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I was vegetarian for 25 years and it was the worst possible diet for me, I now eat less than 30 carbs a day mostly from vegetables and the rest is meat cheese eggs etc. For anyone reading this topic I just want to reiterate that its not something that happens randomly, its a permanent way insulin works in us, it’s ALWAYS two or longer hours, then it just works like normal, it will start coming on really strong, it’s just like a giant delay and then wham business as usual. It’s not from the time you take it or the diet etc, I’ve had diabetes in every life stage, toddler, child, teenager, adult, middle age, this has only been happening for 6 years or so, everyone who has this happen all of them have had diabetes for many decades (obviously though not everyone who has had it for decades will have this problem), so there is some link with time there.
Fred, great topic, until your thread I thought I was alone in this. I too am unaware of hypos now and have a dexcom g5 so I literally sleep with my phone on me. I had a few really scary hypos that were like bad acid trips, I was terrified of having another one. The dexcom g5 on my phone is a life changer.
Becky I saw Bernstein doing IM shots and another girl. The reason I do them all the time now is they are very reliable for me. Bernstein recommended them specifically for bringing high BG down. I saw how useful they were for that and just started using them all the time, It was either 10 mins or 2 hours. I also have a fairly low carb diet so my BG doesnt swing to far out, my high warning is set to 8.1 mmol (140 ). Even with a fairly low carb diet and small standard deviation, waiting two hours for insulin to begin can really get me into trouble, it’s very easy to get distracted waiting that long for all bolus’ and corrections to begin.

I am sorry a vegetarian diet didn’t work for you, I just wanted to let people know a vegan/vegetarian diet is completely possible for most people. But I am for whichever diet works for you!

I am a type 1 and a strict vegan and eat what I want as long as it’s vegan. My last A1C was 6%. I love my whole grains, fruits and veggies!!! I do prebolus half my dose a half hour before I eat. High fat with my food can delay absorption for me and there are a couple of items I have to have a bolus a half hour after I eat. I use humalog in an insulin pump and a Dexcom G6.

So sorry to hear about your insulin delay having nothing to do with high glucose levels. That has to be extremely frustrating. After 60 yrs of having type 1, so far I have seemed to bypass many of the problems long term diabetics have. I have no idea why. I do have two heart stents though which were partly caused from high LDL, because of the Bernstein diet which I followed faithfully for 11 yrs. We all need to follow the diets that work best for our own bodies. My body apparently doesn’t like fat at all. I too was a vegetarian for many years, but it too included fat so it wasn’t healthy for me either. For me at this point low fat plant based with plenty of fruit and vegetables works beautifully.

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I never followed the Bernstein diet and my cholesterol went throught the roof. I ate a vegetarian diet purely out of ideology, I grew up on farms and the killing of animals was horrendous and I quickly became vegetarian. They have now apparently linked statins to causing type 2 diabetes. I like you (I think it is you) can also take one statin a fortnight, I realised this when I had taken about 5 in a 3 month period and the Dr said your cholesterol is great! . I can’t eat fructose anymore as it makes me very ill. I tried to do the raw food plant diet and I was vomiting every day for 6 weeks. I had diahorea and I was very I’ll. Turned out it was the ratio of frucrose to glucose in the apples and other fruits I was eating, frucrose intolerance they call it. So I eat a few veges and some meat to make more bulk otherwise I would be too hungry. With my thread topic I can have a BG of 4.5 mmol (roughly 81) and have 8 units of (say) novorapid and sit down and it wont do anything for two hours (almost set a clock to it), then as the time comes round it will hit me with as much strength as it would on anyone else, the effect isn’t degraded at all, this is the what makes it so strange. At first I thought maybe I had insulin resistance or something but it is purely a delay in action. So now I do IM shots so I get a nice response time. There arw others who have this problem and I would love to get data in them to find out what is going on.

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I share your desire to not harm animals, so was very happy to stop eating them. I hope that I don’t end up with a problem with fructose. Man, we are all such strange creatures. Yes, I just took a very low dose of a statin and was so pleased when my LDL was reduced, but even on a very low dose the side effects, for me, were awful. So, I am sure my LDL level is rising again now that I am once again trying to control it only through exercise and the low fat diet. Sometimes we just can’t seem to win.
We just have to keep trying and celebrating finding what works for us.

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Does it hurt more ?

What other things are their to consider like maybe hitting a nerve or something.

I ask these questions because I am very thin and if the only difference of muscle shot is time why not ?

Too fast a drop no thanks of course.

I do my shots in the rear cause that’s my thickest fat deposit. And the stomach area shots just freaked me out in the beginning.

I do need to start reading again. I was all about learning everything I could in the beginning then I found it was making me worry too much. Then my friend with T-1 calmed me about it , he has been at it 17 years.

I think it was Dr Bernstien stuff I read about doing insulin in the muscle.

I just had my first diabetes burnout, drank excessive alcohol too. No fun, got sick. Watching my health and the gym was a better track.

Interested in this IM use. If I go too high bring it down fast with a very small amount maybe. I am just guessing they don’t want us dropping too fast so IM use is not promoted.

The issue you spoke about partly (not entirely) concerns the fact that injection sites are often different with respect to time for insulin action. Some sites might give delayed response for exactly the same s.c. bolus quantity compared to another. Some burned out site after decades of use can yield delayed and inadequate response due to cutaneous changes over time due to injection trauma and tissue challenges. I think everybody knows this in our culture. OTC Humulin R and NPH are old school and not the best choices unless the cost for the reli-on brand is why one get’s them. First of all the NPH is not really long and most people use less fast to get the same results compared to intermediate R which is out of fashion for a reason. For instance, Degludec is far superior to NPH. So when I hear you combination I sigh a little.

It is commonly known that bolus insulin used for correction takes 4 hours to achieve its effect. Your endo is misinformed. I believe IM works, but I could never stand to do it, OUCH! It makes my hair stand on end just thinking about it, but more power to ya’ if you got the guts to do it.

That’s what I say with the idea if an IM shot but that’s where I was at doing the skin shots in the beginning. Terror actually “you are going to have to learn to do this yourself” wait what , no I am going to wake up from this this is not true…

In an hour I fill a needle and poke push done. No biggy. The dart at the dart board, made that up in my head a few weeks in.

But yes if they told me I had to start doing IM shots right now, I would be troubled.

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It has nothing to do with that at all. Ive been at this game for 43 years, since I was three, I am well aware of all this stuff. I specifically put how long I have been treating myself right at the start to avoid this. I am one of the few who have had this problem my entire life, and approaching half a century. The problem is it now takes 2 hours no matter where I inject it, I’m not alone, this happens to many type ones after multiple decades of type one (not all) most at least 40 years. I must rewrite the thread because it wasn’t meant to be about things people should know in their first few years of the disease, it was how do others with delayed onset insulin absorbtion combat and work with managing it, ie IM injecrions.

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I have to be careful what I say. The first thing to understand about insulin injection, it is some like but mostly NOT like injecting drugs (of any type). For a start it is a hormone, an altered hormone, but after all is said and done it acts like a hormone. Like drugs, the faster the route the quicker the half life (ill get backnto this). So for insulin, there are three main routes, subcutaneous (SC), intramusular (IM), and intravenous (IV). Each one increases with time taken to begin reducing BG. SC being the slowest (all things being even) and IV the fastest. Here is where it takes a turn though, with SC insulin the time to wear off can be (for fast acting) anywhere from 1 hour and 15 mins to 5 or 6 hours. For IM the half life shortens to maybe half that (in me it is an hour and a half), so it will begin quicker but wear off much faster. IV generally being the fastest (although often it can be the same as IM) also is removed from the body very very quickly, sometimes in minutes. When in hospital IV insulin is usually given in a drip because of this fact, it wears off often before it has a chance to act, so is given in small amounts very often, usually in cases of DKA. Another interesting quality of insulin is that it must go through a metabolic process, it wont just start working fast because you introduced it quicker. Many think erroneously that because they have IV insulin it will work immediately and they will come crashing down. It can and generally does start working within 10 minutes but may take up to an hour or two to complete its full cycle, however it can and often does wear off and does very little. You can see there is more to changing routes than meets the eye and this intro, is by no means rigorous. IV is never recommended or needed in the home as it can lead to a host of problems and more importantly it provides very little real time advantage over IM.

Regards IM, I thought it would hurt also but it doesnt really, although like SC it can hurt sometimes, really bad. Ive had some excruciating SC injection over the years, one every few years or so that’s so painful I pull it out and jump up and down and must have another go but none this painful with IM, ymmv. The biggest problem I have had with IM Is hitting a blood vessel and blood coming out of and running down my arm. There is a video of a girl on youtube showing how easy it is. Dont worry, your more likely to not go deep enough than to go too deep

Ok I’m going to stop writing. It is becoming a book.

Its never too early to learn.

“IV insulin has a very short duration of action (minutes)”

“The only type of insulin that should be given intravenously is human regular insulin . There is no advantage to using rapid-acting analogs in preparing insulin infusions because the rate of absorption is no longer a factor when administering insulin intravenously and can only result in added costs to the institution.”

I don’t believe that. I think its still a factor even if small, cutting corners for cost is of less importance.

My search term was “iv insulin administration”

My curiosity about IV insulin administration is for future technology in managing type one. Maybe with trustworthy medical equipment using IV infusion it could be possible to more closely mimic the natural action of beta cells in the pancreas.

And that looping. I would want sugar infusion option too to correct a low as I think the so far somewhat unpredictable nature of insulin would require this.

I would trust that more then artificial intelligence algorithms making predictions. I would want both in a system.